Metal sub-purlin and metal truss cap for use in roof construction

Abstract

A steel sub-purlin for use in roof construction, the sub-purlin being fabricated using metal roll forming techniques. The sub-purlin has an upper, angled portion, a lower angled portion, a vertical section connecting the upper and lower sections and vertical extensions from said upper and lower angled portions positioned in contact with the vertical section. The ends of sub-purlin are positioned on steel truss caps, the truss caps being used in place of conventional wood nailers.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention provides a metal purlin and truss cap for wood roofs having steel framing. [0003] 2. Description of the Prior Art [0004] As noted in U.S. Pat. No. 5,499,480 to Bass, the construction industry has attempted to reduce the use of wood in residential and light commercial developments. This, in turn, will reduce the construction costs, minimize the types of maintenance problems associated with wood, such as insect damage and decay and also significantly reduce the potential damage caused by fire. [0005] A steel framing design for use with wood roofs has been available in the roofing industry for a number of years. In one system, open web steel joists and joist guides are joined with sheathing, thus utilizing the economy and strength of open web steel joists and joist guiders with the low insulation costs and high diaphragm (shear) capacities of a conventional panelized wood roof. In this type of sys...

AI Technical Summary

Benefits of technology

[0009] The present invention provides a steel sub-purlin for use in roof construction whereby the use of wood is reduced, the structural strength of the roof significantly increased and the ability of the roof system to resist shear forces, such as that produced by earthquakes, is increased.

[0012] The present invention thus provides two steel, cold formed components that significantly enhance the shear strength of roofing structures while reducing the disadvantages associated with using wood roofing components.

Problems solved by technology

Although the panelized roof system described hereinabove provides significant advantages over commercial roofing systems comprised almost entirely of wood, the steel framing design still utilizes wood nailers and wood sub-purlins with the attendant disadvantages as noted hereinabove.

In addition, the shear strength of a roof system having wood components is limited.

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